1. Field
This disclosure generally relates to automatic data collection (ADC) devices, methods and articles.
2. Description of the Related Art
The ADC field is generally directed to the use of devices and methods for automatically capturing data typically encoded in media such as a machine-readable symbol or tag carried by the item to which the data relates. A variety of ADC devices and ADC media are ubiquitous and well-known.
For example, a machine-readable data carrier may take the form of a machine-readable symbol, which may be selected from a variety of symbologies and which take the form of a bar code. Some bar coding systems employ standard message channel techniques, such as Basic Channel Model (BCM) techniques, to convey a message between components. Information describing the meaning of the data such as a serial number can be conveyed in the channel using standard techniques such as application identifiers, data identifiers, and text element identifiers. Some bar coding systems may employ out of channel techniques to convey additional information about the message, such as extended channel information (ECI) techniques, including the industry standard Extended Channel Model (ECM), which adds a layer to the BCM to convey additional information about the graphical representation of the data characters or whether the data characters have been compacted.
In another example, a machine-readable data carrier may take the form of a radio-frequency identification (RFID) device or tag, which may take the form of a card or a label. Such tags typically include an RFID substrate carrying circuitry such as a semiconductor device including memory and one or more conductive traces that form an antenna. Typically, RFID tags act as transponders, providing information stored in the semiconductor device in response to a radio-frequency (RF) signal, commonly referred to as an interrogation signal, received at the antenna from a reader or interrogator. Some RFID tags include security measures, such as passwords and/or encryption, which may be added at the system level. Many RFID tags also permit information to be stored in a semiconductor memory via an RF signal.
Due to the proliferation of RFID devices, methods and articles, and the frequent use of RFID devices in close proximity to each other, performance issues have arisen.